how can i disallow spaces or any or even numbers in text box?

how can i disallow spaces or any or even numbers in text box?

• MSatya

  i dont recommend to do it that way... becasue if u use the keypress if the user paste text ur validation will not work.. what i use is textchanged... i get the string that is in the textbox and create a char array ,, then i validate char by char... heres an example. (if u use this often u can create a control...so u stop pasting in each class the method... but what ever... heres the code):
  
  //u create the event for ur textbox text changed.. and send to the method validateInt a textbox control. that u want to validate
  
  private void txtCantidad_TextChanged(object sender, EventArgs e)
  {
  validanumero(txtCantidad);
  }
  
  
  private void validateInt (TextBox sender)
  {
  //a flag to define if it should select the end of the text so it looks pretty :P
  bool selectEnd = false;
  // the string newText will be the final result
  string newText = null;
  //here its gets the text of sender.. sender is the textbox that u sent
  string txt = sender.Text;
  //creates an array of chars of ur textbox text
  char[] txtArray = txt.ToCharArray();
  //for each character it starts the validation
  foreach (char car in txtArray)
  {
  //i car is > 47 and < 58 the its a valid character and add to newtext the character... if u dont know what is 47 and 48 look in google for an ASCII table and each character contains a number... thats it
  if (car > 47 && car < 58)
  {
  newText = newText + car;
  }
  //heres what i said about selecend... if the character is not valid then it will select the last part of the text.. if u dont understand me,, just dont do it and check out what happen :)
  else
  {
  selectEnd = true;
  }
  }
  //ok,,now it ended and the text of the text is = to newText;
  sender.Text = newText;
  //now figures out what part of the text to select .. as i said if uj didnt get my point on here :P ,, remove it and check out ;)
  if (selectEnd == true)
  {
  int x = 0;
  try
  {
  x = newText.Length;
  }
  catch (Exception)
  {
  newText = "";
  }
  sender.SelectionStart = x;
  }
  }
  
  hope it helps... if u need to validate floats just change the characters number and there u go ;)
  
  

• ToroLocoMex

  hi ,

  actually im learning c# now and im not good enough yet by enevts if i dont bother you can u write the code please so i guess i can understand how does it works .

  thx

  
  
  

• tim_baxter

  Handle the KeyPressed event and if the key passed in through the event args is not one you want, then sent e.Handled = true;

  Be careful tho, if char.IsControl returns true, you want to leave e.Handled, otherrwise the arrows, etc will not work.

  
  
  

• adimasi

  hi,

  you can try something like this

  public partial class Form1 : Form { public Form1() { InitializeComponent(); //keypress event this.textBox1.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBox1_KeyPress); } private void textBox1_KeyPress(object sender, KeyPressEventArgs e) { //first character in this string is space string rejectthose = " ><,-+{}[]"; if (rejectthose.IndexOf(e.KeyChar) > -1) { MessageBox.Show("you can't use this character " + e.KeyChar); e.Handled = true; } } }

  hope this helps

  
  
  
• how can i disallow spaces or any or even numbers in text box?